Skyfarming, or growing food on the vertical plane rather than the horizontal, is usually the preserve of sci-fi scenarios where the gardeners probably need jet-packs to tend their plants. But a 9m tall food garden is being constructed as I write in London, for the Chelsea Flower Show, the UK's top garden show.

One wall of the steel-frame structure is entirely plants, the other entirely solar photovoltaic panels. The panels power the water pumps that push water from a borehole round the hydroponic growing system. Inside the tower, along with the stairs are greenhouse areas for propagation, and a compost chute.

On the wall, are large window boxes, for plants including tomatoes, peppers and nasturtiums, said Patrick Collins, a landscape architect who designed the B&Q-sponsored garden with architect Laurie Chetwood. Alongside the boxes is a wall of herbs that thrive when clipped, such as thyme, camomile and oregano.

Chetwood acknowledges that people aren't going to put a 9m tower in their city gardens. "But the good thing about Chelsea is it's about larger than life ideas. Our garden is meant to be inspirational but have within it some practical ideas people can take away."

The 'bedrooms' in the insect hotel were designed by school children. Photograph: ZPR

"Our garden is saying anyone can grow their own veg, even in a small garden or a window box," added Collins.

Everything in the garden is edible, even the trees, says Collins: the vertically trimmed lime trees have flowers that can make a herbal tea, while the mulberry trees give a crunchy berry.

"Ninety percent of our food comes from just 20 species of plant," Collins told me. "But there are 100s of edible plants in the world, so our garden illustrates that." One unusual plant is Stevia rebaudiana, which has a very sweet taste and can be used as a sugar substitute, he says.

There is also an insect hotel, where the 90 "bedrooms" have been designed by children. "Some were very literal in their interpretation, and made little beds for earwigs," says Chetwood. "The serious point is to encourage people to establish ecology in their gardens, where these [insects] are getting hammered."

"They say there are only four days of food in London," says Chetwood. "There's a big drive in London to grow more food." As a recent convert to gardening in my tiny city garden, striking ideas certainly act as an inspiration.

WorldSkills London 2011's "Showcasing Skills that Shape our World" picks up a silver gilt medal, while WorldSkills competitors Joe Massie and Jessica Andrews scoop up the Young Florist of the Year and Bronze respectively